Not necessarily. While being called a "best friend" can be a sign that the person values your friendship and connection, it doesn't automatically mean you are stuck in the friend zone. People often use the term "best friend" to describe someone they trust and have a close bond with, which can be a positive thing.
Whether you are in the friend zone or not depends on the context of your relationship and the feelings both of you have towards each other. It's possible that the girl sees you as a close friend but hasn't considered a romantic relationship yet. However, this doesn't mean that her feelings can't change in the future.
If you have romantic feelings for this girl and want to explore the possibility of a deeper relationship, it's essential to communicate openly and honestly with her. Have a conversation about your feelings and ask about hers. Remember that genuine friendships can be the foundation for successful romantic relationships, so it's not necessarily a negative thing to start as friends.
Keep in mind that everyone's feelings and preferences are unique, so there's no one-size-fits-all answer to this question. The key is to be respectful of her feelings and decisions while also expressing your own in a clear and considerate manner. Communication and understanding are crucial in any relationship, whether it's romantic or platonic.